The density of a potato is an important indicator that affects its taste and performance characteristics. This food crop is referred to as the “second bread”, which has a universal application.
Composition of tubers
In order to determine the effect of potato density on its palatability, let's analyze its composition. The average content of starch in tubers ranges from 14-22%, protein - 3%. This culture contains the glycoside solanine. Its content leaves 1-5 mg per 100 grams of raw potatoes, the concentration is higher in the peel.
The density of potatoes depends on the variety, the conditions for growing tubers. If the content of alkaloids does not exceed 23-27 mg per 0.1 kg, the product is not dangerous to humans. Otherwise, there is a high probability of serious poisoning.
Classification
Taking into account the economic purpose, all varieties are divided into groups:
- factory;
- canteens;
- universal;
- feed.
Table varieties have a high density of potatoes, excellent taste characteristics, light flesh. Such tubersmelt quickly, but they do not crumble. These varieties are characterized by a short growing season, so they can be grown in the northern regions.
The density of technical varieties of potatoes is slightly less, the tubers contain up to 18 percent of starch. These varieties have excellent fermentability, so they are suitable for industrial production of alcohol. Universal types have low taste indicators, they occupy an intermediate position between factory and table types.
Historical information
South America is considered the birthplace of the potato. It was on the coast of Chile and the adjacent islands that the ancient Indians began to use the roots of wild potatoes about 14 thousand years ago. The first mention of this culture was made by the Spanish soldier Pedro Chieso de Leon, who became a member of a military expedition to South America. Despite these records, it was not until the second half of the sixteenth century that the potato began to be used by Europeans. It was then that Spanish ships brought "peanuts", which became the progenitors of modern European potatoes.
In our country, potatoes appeared only in 1698. It was then that Peter I from Rotterdam sent a bag of tubers for propagation. For decades, this culture has been propagated by both seeds and tubers. By the end of the 19th century, about a hundred varieties of this agricultural crop were bred. At the moment, about 7 million hectares are allocated for potato fields.
BiologicalFeatures
This herbaceous perennial plant belongs to the nightshade family. Its reproduction is carried out in a vegetative way: cuttings, sprouts, tubers.
The genus Solanum includes just over two hundred tuberous potato species. The fruit grown from a tuber has a fibrous root system consisting of several individual stems. Their width and length depend on the variety, climatic conditions, moisture and soil composition.
Potato density g/cm3 depends on its age. As the tuber grows, it increases, as a thick integumentary tissue appears.
For breathing, there are small lentils, which are dark spots on the skin of potatoes. Through such holes, air enters it, water vapor and carbon dioxide leave.
There are differences in color, shape of tubers depending on the variety. It contains about 75% water, up to 21% starch, 1% ash and fiber each, 2% protein, and also has a small amount of sugar and fat.
The fruit of the potato is a juicy multi-seeded green berry with a pleasant strawberry smell. They are high in the alkaloid solanine, making potatoes unsuitable for consumption.
Determination of starch content by Parov's scales
In order to find out what the density of potatoes is, you can use a potato scale. The larger this value, the higher the content of starch and dry matter in the tubers.
You can determine the density of potatoes in physics using the lawArchimedes. Given that a body that is immersed in a liquid will lose as much mass as the volume of water it can displace. For this reason, the mass of a potato in air exceeds the value for a tuber immersed in a liquid.
The density of a potato in physics is determined by the ratio of the mass of potatoes in air to the mass of water that has been displaced. Experimental results are used for calculations.
Bulk density of potatoes - a tabular value by which you can determine the percentage of starch in tubers.
With the help of special weights, not only starch content is calculated, but also the contamination of tubers. The device is a rocker with different shoulders. On the short part there is a movable large weight to balance the scales, as well as an earring with wire baskets located one above the other.
The upper part is left in the air, and the lower part is immersed in a tank of water. There are two parallel rulers on the long part of the rocker arm. On one of them a small movable weight is installed, and on the second - a large load with a built-in movable ruler. The back part is used for weighing potato samples, as well as for detecting contamination. The scale is graduated, expresses the percentage of impurities.
The balance must be balanced before proceeding with the detection of potato starchyness.
The volumetric weight of potatoes is determined using scales without changing the location of the baskets. The percentage of contamination is calculated by moving the weight on the rocker to balance the balance.
To that division value, bywhich the tip of the pointer pin stops, add 1% - an amendment for water. For example, with four divisions, the percentage of contamination will be 5.
Frozen product calculations
When determining the starchy content of a potato frozen at a time, as well as a slightly frozen tuber, it is first kept in water at 40-50 ° C (thawed). Then large tubers are cut with a knife, first making sure that there are no frozen areas.
The thawed tuber is placed on a baking sheet, then doused with cold water. Next, the determination of starch content is carried out according to the same method as for ordinary potatoes.
As the potato thaws, cell juice is lost, so one percent is subtracted from the resulting starch size of the frozen tuber.
If there is rot in the potato, first it is cut out with a knife, only after that the starch content is calculated using a method similar to he althy potatoes.
Calculation of density and starch content for samples that have been repeatedly frozen
In appearance, these potatoes have significant differences from he althy samples. The tubers are shriveled, have a darkened skin, and float to the surface when immersed in water.
Since the tubers of this potato have lost a significant amount of water, it will not be possible to determine its density and starch content with ordinary potato weights. For such purposes, the polarimetric method is used. The sample is ground into gruel on a fine grater. 100 grams of sample wash off 50ml hydrochloric acid (1.124%), place the flask in a water bath for 20 minutes.
Polarization is carried out in a tube 10 cm long. Polarimeter readings are multiplied by a special Evers coefficient characterizing potatoes, and the % of starch content in it is obtained.
Interesting facts
Potato is a crop that is suitable for a temperate climate, but man has managed to adapt it to the northern latitudes. Tubers germinate at soil temperatures from +7 to +12 °C. With its increase, the tubers develop faster, so you can count on getting dense and large fruits.
Biologists recommend pre-sprouting potatoes to reduce growing time in soil. To grow dense tubers with high taste, it is desirable to create a soil moisture of 70-80 percent, the soil should warm up to +16 to +22 ° С. Potato is a photophilous short-day plant. If the amount of sunlight is insufficient, in this case the tubers are loose and tasteless. Soil moisture also affects this indicator. With insufficient watering, plant growth slows down, small and loose tubers are formed that are not suitable for nutrition.
Conclusion
At present, it is the potato that is considered one of the most common crops among domestic gardeners, its planting is carried out not only in the central, but even innorthern regions of our country.
To obtain high-density tubers with the highest taste indicators, it is necessary to observe the temperature regime, control soil moisture, and periodically apply mineral fertilizers to it.
The greatest amount of moisture is necessary for this plant at the stage of flowering, the birth of fruits. Any violations of humidity during this period lead to a change in the density of the potato, a decrease in its taste.
Certain requirements apply to minerals used for feeding. During the growing season it is necessary to apply nitrogen fertilizers. Phosphorus and potash fertilizers are used to increase the density of potato tubers.
